Fix unused imports (ruff lint)

Author: claude

src/datajoint/external.py

@@ -5,15 +5,14 @@
 
 from tqdm import tqdm
 
-from . import errors
 from .declare import EXTERNAL_TABLE_ROOT
 from .errors import DataJointError, MissingExternalFile
 from .hash import uuid_from_buffer, uuid_from_file
 from .heading import Heading
 from .settings import config
 from .storage import StorageBackend
 from .table import FreeTable, Table
-from .utils import safe_copy, safe_write
+from .utils import safe_write
 
 logger = logging.getLogger(__name__.split(".")[0])
 

src/datajoint/storage.py

@@ -6,7 +6,6 @@
 """
 
 import logging
-from io import BytesIO
 from pathlib import Path, PurePosixPath
 from typing import Any